KR101825613B1 - Method for preparing low-odor polyethylene resin composition for plastic closure and Article Produced with the Same - Google Patents

Abstract

A preparation method of a polyethylene resin composition for a bottle cap of the present invention, as a method of preparing the polyethylene resin composition by copolymerizing ethylene and alpha-olefin in the presence of a solid catalyst including Si, Ti and Mg, comprises performing a degassing process of at least three stages or more on the polyethylene resin composition, wherein the degassing process of the three stages or more has a first stage pressure of 1.2 to 1.5 atmospheric pressure, a second stage pressure of 1.1 to 1.3 atmospheric pressure, and a third stage pressure of 0.9 to 1.1 atmospheric pressure. The polyethylene resin composition has less than 10 ppm of a content of a hydrocarbon having 2 to 10 carbon atoms, exhibits low bad odor characteristics with a smell index of 2.0 or less, and does not generate an unpleasant smell such that the polyethylene resin composition can maintain intrinsic smell characteristics of the beverages when the polyethylene resin composition is applied to the bottle cap for beverages.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyethylene resin composition for a plastic bottle cover showing low odor characteristics and a molded article produced therefrom,

The present invention relates to a polyethylene resin composition for a plastic bottle cap which does not cause an unpleasant odor by reacting ethylene oxide and tetravalent titanium compound with an organomagnesium compound and copolymerizing and degassing ethylene and an alpha olefin in the presence of a solid catalyst containing an alkoxysilane compound And a molded article produced therefrom.

In recent years, plasticization of bottle lids used in beverage containers such as glass bottles and polyethylene terephthalate (PET) has been increasing due to diversification of packaging containers and separation of environmental aspects. High density polyethylene, polypropylene, etc. are mainly used as plastic bottle lid material. Bottle lid based on these materials is light and not corrosive compared with conventional aluminum bottle lid. Its use is increasing as a possible advantage. Especially, high density polyethylene has flexible characteristics compared to polypropylene, so it is possible to maintain the sealing property of the contents without using a liner, unlike a bottle cap made of polypropylene, which requires a separate liner to seal the contents of the beverage container . However, if there is a component that causes odor in the polyethylene resin, the component may be transferred to the beverage to change the intrinsic odor of the beverage, and if unpleasant, the odor may occur. Particularly, in the case of bottled water, tasteless odor must be maintained, and a small amount of odor causing substances remaining in the PET container or the polyethylene bottle lid continuously changes the taste of the living water.

US Patent No. 5,948,846 discloses a method of adsorbing an odor component by adding a lubricant and zeolite to a resin composition in the prior art. However, the present invention, which minimizes odor of the resin by using a method using additives, There is a difference.

It is an object of the present invention to solve the above-mentioned problems and to provide a method for producing a polyethylene resin composition for a plastic bottle cap for a beverage in which odor induction of a polyethylene resin is minimized.

Another object of the present invention is to provide a molded article produced by the above production method.

According to an aspect of the present invention,

A process for producing a polyethylene resin composition by copolymerizing ethylene and an alpha olefin in the presence of a solid catalyst comprising Si, Ti and Mg,

The polyethylene resin composition is subjected to a degassing process of at least three stages,

Wherein the pressure of the first stage of the degassing process of the three or more stages is 1.2 to 1.5 atm, the pressure of the second stage is 1.1 to 1.3 atm and the pressure of the third stage is 0.9 to 1.1 atm. And a method for manufacturing the same.

The polyethylene resin composition prepared by the process for producing a polyethylene resin composition of the present invention exhibits a low odor characteristic, and when applied to a bottle cap for a beverage, the odor characteristic inherent to the beverage can be maintained.

Hereinafter, the present invention will be described in more detail.

A process for producing a polyethylene resin composition by copolymerizing ethylene and an alpha olefin in the presence of a solid catalyst comprising Si, Ti and Mg,

The polyethylene resin composition is subjected to a degassing process of at least three stages,

Wherein the pressure of the first stage of the degassing process of the three or more stages is 1.2 to 1.5 atm, the pressure of the second stage is 1.1 to 1.3 atm and the pressure of the third stage is 0.9 to 1.1 atm. And a manufacturing method thereof.

In one embodiment of the present invention, the polyethylene resin composition prepared by copolymerization of ethylene and alpha-olefin is preferably subjected to at least three degassing steps.

The degassing process of the three or more stages may include a step of degassing the degasser at a first stage pressure of 1.2 to 1.5 atm, a second stage pressure of 1.1 to 1.3 atm and a third stage pressure of 0.9 to 1.1 atm.

In the present invention, a chain hydrocarbon having a carbon number of 2 to 10 is removed from the polyethylene resin composition, which is analyzed by headspace-gas chromatography, through a deaeration process of a powdery polymer produced in the reactor, By weight or less.

The degassing process may proceed in at least three stages in the degassing apparatus, and the degassing process conditions may affect the content of short chain hydrocarbons having 2 to 10 carbon atoms in the polymer.

In order to keep the hydrocarbon content of the short chain carbon chain of 2 to 10 in the polyethylene resin composition at less than 10 ppm, the degasser requires a first stage pressure of 1.2 to 1.5 atm, a second stage pressure of 1.1 to 1.3 atm, And is preferably in the range of 0.9 to 1.1 atm.

In one embodiment, the productivity of the deaerator is lowered when the pressure of the first stage is less than 1.2 atm. If the pressure is more than 1.5 atm, the deaeration is not properly performed.

If the above-mentioned two-stage pressure is less than 1.1 atmospheres pressure, the productivity is lowered.

If the above-mentioned third-stage pressure is less than 0.9 atm, the discharged polymerized polyethylene powder is not smoothly discharged.

Also, the first-stage pressure must always be greater than the second-stage pressure, and the second-stage pressure must be greater than the third-stage pressure, thereby smoothly transferring the powder.

In one embodiment, the polyethylene resin composition preferably has a short chain hydrocarbon content of 2 to 10 carbon atoms of less than 10 ppm, and if the hydrocarbon content is more than 10 ppm, it can not exhibit sufficient low odor characteristics.

In one embodiment, the polyethylene resin composition preferably has a sensory score of 2.0 or less, and an unpleasant odor may occur when the polyethylene resin composition exceeds 2.0.

In one embodiment, the ethylene and alpha olefin copolymerization may be carried out in the presence of a solid catalyst comprising Si, Ti and Mg at a polymerization pressure of 30 kg / cm ² or less and at a polymerization temperature of 40 to 120 ° C.

In one embodiment, the polymerization reaction is carried out by continuously introducing monomers composed of ethylene or other alpha-olefins into the reactor filled with gaseous ethylene, by contacting the gaseous monomers directly with the catalyst system. The polymerization is generally carried out in the presence of a chain growth inhibitor such as hydrogen to control the molecular weight of the polymer, and it is preferable that the volume ratio of hydrogen used for the olefin used in the reaction ranges from 1 to 10%.

In one embodiment, the melt flow index of the polyethylene resin composition is 0.5 to 30 g / 10 min, preferably 1 to 20 g / 10 min, measured at 190 ° C under a load of 2.16 kg ASTM D1238.

When the melt flow index is less than 0.5 g / 10 min, flowability is lowered and bottle lid molding is difficult. When the melt flow index exceeds 30 g / 10 min, the environmental stress crack resistance (ESCR) .

In one embodiment, the density of the polyethylene resin composition is 0.945 ~ 0.965g / cm ^3, preferably 0.950 ~ 0.960g / cm ^3. If the density is less than 0.945 g / cm ^3, the sealing properties of the bottle lid may deteriorate due to a decrease in the bending strength. If the density exceeds 0.965 g / cm ³ , the environmental stress crack resistance (ESCR) There may be a problem with stability.

In one embodiment, the polyethylene resin composition may further comprise an antioxidant and a neutralizing agent.

The antioxidant may be included in an amount of 0.01 to 0.5 parts by weight, preferably 0.05 to 0.2 parts by weight based on 100 parts by weight of the total amount of the polyethylene resin composition.

If the content of the antioxidant is less than 0.01 parts by weight, discoloration during storage and viscosity change during processing may occur. If the content of the antioxidant is more than 0.5 parts by weight, there may be a problem that the taste and odor are deteriorated.

The neutralizing agent may be included in an amount of 0.01 to 0.3 parts by weight, preferably 0.05 to 0.2 parts by weight based on 100 parts by weight of the total amount of the polyethylene resin composition.

If the content of the neutralizing agent is less than 0.01 parts by weight, discoloration and viscosity change during processing may occur. If the amount of the neutralizing agent is more than 0.3 parts by weight, changes in physical properties such as color and strength may occur.

Representative examples of the antioxidant include 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene (1,3,5- , 4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, 1,6-bis [3- (3,5- (3,5-di-tert-butyl-4-hydroxyphenyl) propionamido] hexane), 1,6-bis [3- Butyl-4-hydroxyphenyl) propionamido] propane), tetrakis [methylene (3,5 4-hydroxyhydrocinnamate)] methane), bis (2,6-di-tert-butyl-4-hydroxyhydrocinnamate) Butyl-4-methylphenyl) pentaerythritol-di-phosphite), tris (2,4-di-tert- butylphenyl) pentaerythritol- ) Phosphite and bis (2,4-di-tert-butylphenyl) pentaerythritol-di-phosphite (Bis (2,4-di-tert-butylphenyl) Pentraerythritol-di-phosphite) and the like.

Representative examples of such neutralizing agents may include calcium stearate, zinc stearate, magnesium aluminum hydroxycarbonate, zinc oxide and magnesium hydroxystearic acid or mixtures thereof.

In one embodiment of the present invention, the solid catalyst may preferably be prepared comprising the following steps.

(1) reacting metallic magnesium (Mg) with an organic halide compound represented by the following formula (1) to produce an organic magnesium halide;

≪ Formula 1 >

R ¹ X

(Wherein R &^lt; 1 > is an alkyl group having 1 to 10 carbon atoms, X is chlorine, bromine or iodine)

(2) reacting a titanium tetravalent titanium compound represented by the following formula (2) in the reaction of step (1) to prepare a catalyst intermediate; And

(2)

Ti (OR ² ) _m Cl _{4 -m}

(Wherein R ² is an alkyl group having 1 to 10 carbon atoms, m is an integer of 0 to 4, or a prime number)

(3) adding an alkoxysilane compound represented by the following formula (3) to the solid catalyst during the reaction of step (2) or after completion of the reaction of step (2);

(3)

R ³ _n Si (OR ⁴ ) _{4 -n}

(Wherein R ³ and R ⁴ are each an alkyl group having 1 to 10 carbon atoms, n is an integer of 0, 1 or 2, and when n is 2, two R ^{4 s} are the same or different).

Examples of the alkoxysilane compound represented by R ³ _n Si (OR ⁴ ) _{4 - n} used as the electron donor material in the step (3) include tetramethoxysilane, methyltrimethoxysilane, dimethyltrimethoxysilane , Trimethylmethoxysilane, ethyltrimethoxysilane, diethyldimethoxysilane, triethylmethoxysilane, vinyltrimethoxysilane, divinyldimethoxysilane, propyltrimethoxysilane, dipropyldimethoxysilane, tripropyl But are not limited to, methoxysilane, isopropyltrimethoxysilane, diisopropyldimethoxysilane, triisopropylmethoxysilane, butyltrimethoxysilane, dibutyldimethoxysilane, tributylmethoxysilane, isobutyltrimethoxysilane, Diisobutyldimethoxysilane, diisobutyldimethoxysilane, triisobutylmethoxysilane, cyclopentyltrimethoxysilane, dicyclopentyldimethoxysilane, cyclopentylmethyldimethoxysilane, cyclohexyltrimethoxysilane, dicyclohexyldimethoxysilane , Cyclohexylmethyldimethoxysilane, tetraethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, trimethylethoxysilane, ethyltriethoxysilane, diethyldiethoxysilane, triethylmethoxysilane, vinyltriethoxysilane, Propyltriethoxysilane, dipropyldiethoxysilane, tripropylethoxysilane, isopropyltriethoxysilane, diisopropyldiethoxysilane, triisopropylethoxysilane, butyltriethoxysilane, dipropyltriethoxysilane, dipropyltriethoxysilane, But are not limited to, ethoxysilane, dibutyldiethoxysilane, tributylethoxysilane, isobutyltriethoxysilane, diisobutyldiethoxysilane, triisobutylethoxysilane, cyclopentyltriethoxysilane, dicyclopentyldiethoxysilane, Cyclopentylmethyldiethoxysilane, cyclohexyltriethoxysilane, dicyclohexyldiethoxysilane, cyclohexylmethyldiethoxysilane, tetrapropoxysilane, methyltripropoxysilane, methyltripropoxysilane, Methyldipropoxysilane, trimethylpropoxysilane, ethyltripropoxysilane, diethyldipropoxysilane, vinyltripropoxysilane, divinyldipropoxysilane, propyltripropoxysilane, dipropyldipropoxysilane, Isopropyltripropoxysilane, diisopropyldipropoxysilane, butyltripropoxysilane, dibutyldipropoxysilane, isobutyltripropoxysilane, diisobutyldipropoxysilane, cyclopentyltripropoxysilane, cyclopentyltripropoxysilane, , Dicyclopentyldipropoxysilane, cyclopentylmethyldipropoxysilane, cyclohexyltripropoxysilane, dicyclohexyldipropoxysilane, and cyclohexylmethyldipropoxysilane. Of these, one or two of them Or more can be used.

In one embodiment, the respective reactions in steps (1), (2), and (3) of the solid-phase synthesis method are carried out in the presence of an organic solvent. Examples of the organic solvent include hexane, heptane, Aromatic hydrocarbons such as toluene and xylene as well as aliphatic hydrocarbons such as hexane, methylcyclopentane, octane, isooctane, nonane, decane and kerosene may be used and more preferably hexane, heptane, cyclohexane, methylcyclopentane, Octane and isooctane can be used.

The reactions of steps (1), (2) and (3) are carried out at a temperature of 20 to 150 ° C., preferably 60 to 90 ° C., for efficient reaction.

In the present invention, the solid catalyst can be suitably used for ethylene polymerization in the gas phase or copolymerization of ethylene and other alpha olefins.

The solid catalyst may be added directly to the polymerization reactor in the presence of a cocatalyst during polymerization or may be introduced into a prepolymer prepared by the prepolymerization of one or more olefins in the presence of a cocatalyst in an inert liquid such as an aliphatic hydrocarbon, May be introduced into the reactor.

The ratio of the cocatalyst to the solid catalyst (the molar ratio of aluminum atoms in the cocatalyst to the titanium atom in the solid catalyst) is in the range of 0.5 to 1,000, and the characteristics of each step in the gas phase process, slurry process, solution process, And may be variously used depending on the characteristics of the polymer.

The cocatalyst is characterized by being represented by the following formula (4).

≪ Formula 4 >

AlR ⁵ ₃

(Wherein R < ⁵ > is an alkyl group having 1 to 16 carbon atoms)

Examples of the trialkylaluminum compound include trialkylaluminum compounds such as triethylaluminum, trimethylaluminum, trinormalpropylaluminum, trinormalbutylaluminum, triisobutylaluminum, trinormalhexylaluminum, tri N-octylaluminum and tri-2-methylpentylaluminum, and at least one selected from triethylaluminum, triisobutylaluminum, trinormalhexylaluminum and trinormaloctylaluminum is preferable.

The polyethylene resin composition according to the present invention can be used for general bottle lid manufacturing molding methods such as compression and injection molding, and can provide a molded article manufactured by the above-mentioned manufacturing method.

Hereinafter, the present invention will be described in more detail with reference to the following examples and comparative examples so that those skilled in the art can easily carry out the present invention. The following examples are only illustrative of the present invention and do not limit the scope of protection of the present invention.

Example  1 to 2 and Comparative Example  1-3

Preparation of Catalyst

47.8 g (1.968 mol) of magnesium and 5.0 g (0.02 mol) of iodine were suspended in 2400 ml of purified heptane in a 5 L glass reactor equipped with a mechanical stirrer. 44.9 ml (0.165 mol) of tetrabutoxy titanium and 22.8 ml (0.205 mol) of titanium tetrachloride were poured into the mixture, and 318 ml (3.05 mol) of 1-chlorobutane was added thereto over a period of 4 hours . After the completion of the addition, a further reaction was carried out for 2 hours, followed by washing with a sufficient amount of hexane four times. Then, 8.240 ml (0.037 mol) of tetraethoxysilane was added thereto, followed by further reaction at 60 ° C for 1 hour. The catalyst thus obtained was stored in purified hexane in a slurry state.

Total titanium: 7.8 wt.% (Tetradentate titanium is 78 wt.% In total titanium), magnesium: 32.8 wt.%, Silicon: 0.06 wt.%,

Ethylene and alpha-olefin copolymerization and degassing

Polyethylene was polymerized and degassed in a gaseous fluidized bed reactor with trinormaloctylaluminum (TnOA) as a cocatalyst and the catalyst prepared as described above and the polymerization conditions shown in Table 1 below.

Granulation

0.02 part by weight of Irganox-1010 (Tetrakisethylene (3,5-di-t-butyl-4-hydroxyhydrocinnamate) methane) as an antioxidant, 0.02 part by weight of Irgafos-168 (Tris (2,4- t-butylphenyl) phosphite and 0.1 part by weight of calcium stearate as a neutralizing agent were mixed in a Henschel mixer and then granulated in the form of a pellet using a twin-screw extruder.

Comparative Example  4 to 5

Preparation of Catalyst

47.8 g (1.968 mol) of magnesium and 5.0 g (0.02 mol) of iodine were suspended in 2400 ml of purified heptane in a 5 L glass reactor equipped with a mechanical stirrer. 44.9 ml (0.165 mol) of tetrabutoxy titanium and 22.8 ml (0.205 mol) of titanium tetrachloride were poured into the mixture, and 318 ml (3.05 mol) of 1-chlorobutane was added thereto over a period of 4 hours . After completion of the addition, an additional reaction was carried out for 2 hours, followed by washing 4 times with a sufficient amount of hexane. The catalyst thus obtained was stored in purified hexane in a slurry state.

Total titanium: 7.8 wt% (tetravalent titanium is 78 wt% of total titanium), magnesium 32.8 wt%

Ethylene and alpha-olefin copolymerization and degassing

Polyethylene was polymerized and degassed in a gaseous fluidized bed reactor with trinormaloctylaluminum (TnOA) as a cocatalyst and the catalyst prepared as described above and the polymerization conditions shown in Table 1 below.

Granulation

0.02 part by weight of Irganox-1010, 0.1 part by weight of Irgafos-168 as an antioxidant and 0.1 part by weight of calcium stearate as a neutralizing agent were mixed in a Henschel mixer and then granulated in the form of pellets using a twin screw extruder .

Comparative Example  6

Borouge's Cap HDPE product MB6561

Comparative Example  7

Sabic's cap HDPE product CC453

unit Example Comparative Example One 2 One 2 3 4 5 Polymerization conditions Polymerization temperature ℃ 90 90 90 90 90 90 90 Polymerization pressure kg / cm ² 19.5 19.5 19.5 19.5 19.5 19.5 19.5 Ethylene (C2) mol% 43.3 38.2 43.3 38.2 39.3 42.4 39.3 Hydrogen (H2) mol% 21.2 14.5 21.2 14.5 14.2 21.3 14.2 H2 / C2 - 0.49 0.38 0.49 0.38 0.39 0.49 0.39 1-butene mol% 0.0021 0 0.0021 0 0.0021 0.0021 0 1-hexene mol% 0 0.0013 0 0.0013 0 0 0.0013 Bed Weight kg 80 80 80 80 80 80 80 Residence time hr 12 12 12 12 12 12 12 output kg / hr 7 7 7 7 7 7 7 Degassing conditions Single-stage pressure atmospheric pressure 1.40 1.40 1.40 1.55 1.40 1.40 1.40 Double-stage pressure atmospheric pressure 1.20 1.20 1.35 1.20 1.20 1.20 1.20 Three-stage pressure atmospheric pressure 1.00 1.00 1.00 1.00 1.15 1.00 1.00

Melt flow index (melt index, MI)

Lt; RTI ID = 0.0 > 190 C < / RTI > according to ASTM D1238

density

Measured according to ASTM D1505.

Short chain hydrocarbon content

1 g of the polyethylene resin composition in the form of pellets was placed in a 20 ml vial for headspace gas chromatography and sealed. The mixture was heated to 180 ° C for 1 hour and then subjected to gas chromatography with a DB-5 column (60 m x 0.32 mm x 1.0 m) 10 was determined.

Sensory score

100 g of the polyethylene resin composition in the form of pellets and 1 g of Evian water are placed in a 1 L Erlenmeyer flask made of glass and sealed as shown in Table 2 below. This is allowed to stand in an oven at 80 ° C for 2 hours, then taken out and cooled to room temperature for 1 hour. After shaking it three to five times by hand, open the stopper to take the smell and write the number in accordance with the table below as compared to Blank (prepared under the same conditions without adding resin). The odor evaluator consists of a total of 6 people and results in averages. The odor evaluator is for those who have had more than 10 of these evaluations within 2 hours, who do not smoke, drink, or eat food, and who do not drink or use cosmetics within 24 hours.

Sensory score Criteria One Similar to Blank, it is hard to distinguish. 2 I feel a slight smell. 3 An unpleasant smell is felt. 4 The unpleasant smell feels strong. 5 It smells very disgusting.

unit Example Comparative Example One 2 One 2 3 4 5 6 7 MI 2.16 g / 10 min 7.8 4.6 7.6 7.5 7.6 7.9 4.4 1.5 3.8 density g / cm ³ 0.957 0.960 0.967 0.960 0.957 0.957 0.960 0.959 0.955 short chain hydrocarbon content ppm 7 8 16 12 15 8 8 46 12 Odor index 1.8 1.7 2.4 2.3 2.2 2.6 2.4 3.1 2.8

As shown in Table 3, Examples 1 and 2 were copolymerized in the presence of a solid catalyst containing Si, Ti, and Mg, and all of the three-stage degassing conditions were satisfied, Results.

However, Comparative Examples 1 to 3 were copolymerized in the presence of a solid catalyst containing Si, Ti and Mg, but did not satisfy the three-stage degassing condition, exceeded 10 ppm of the short chain hydrocarbon content, and the odor index Is 2 or more.

Comparative Examples 4 and 5 contain Ti and Mg, but are copolymerized in the presence of a solid catalyst containing no Si, resulting in an unpleasant odor with an odor index of 2 or more as compared with Examples 1 and 2.

Also, in Comparative Examples 6 and 7 of high-density polypropylene products commonly used, the hydrocarbon content of the short chain is more than 10 ppm as compared with Examples 1 and 2, and the odor index shows an undesirable result.

Therefore, the polyethylene resin composition of the present invention, which is produced using a solid catalyst containing Si, Ti and Mg, exhibits low odor characteristics and does not generate an unpleasant odor, so that when applied to a lid for a beverage bottle, .

Claims (10)

A process for producing a polyethylene resin composition by copolymerizing ethylene and an alpha olefin in the presence of a solid catalyst comprising Si, Ti and Mg,
The polyethylene resin composition is subjected to a degassing process of at least three stages,
The pressure of the first stage of the degassing process is 1.2 to 1.5 atm, the pressure of the second stage is 1.1 to 1.3 atm, the pressure of the third stage is 0.9 to 1.1 atm,
Wherein the polyethylene resin composition has a hydrocarbon content of 2 to 10 carbon atoms of less than 10 ppm and an odor index of 2.0 or less.
delete delete The method according to claim 1,
Wherein the polyethylene resin composition has a melt flow index (ASTM D1238, 190 占 폚, 2.16 kg) of 0.5 to 30 g / 10 minutes.
The method according to claim 1,
Wherein the density of the polyethylene resin composition (ASTM D 1505, 23 ° C) is 0.945 to 0.965 g / cm ³ .
The method according to claim 1,
Wherein the polyethylene resin composition further comprises 0.01 to 0.5 parts by weight of an antioxidant and 0.01 to 0.3 parts by weight of a neutralizing agent based on 100 parts by weight of the total of the polyethylene resin composition.
The method according to claim 1,
Wherein the solid catalyst is prepared by the following steps:
(1) reacting metallic magnesium (Mg) with an organic halide compound represented by the following formula (1) to produce an organic magnesium halide;
≪ Formula 1 >
R ¹ X
(Wherein R ¹ is an alkyl group having 1 to 10 carbon atoms, and X is chlorine, bromine or iodine)

(2) reacting a titanium tetravalent titanium compound represented by the following formula (2) in the reaction of step (1) to prepare a catalyst intermediate; And
(2)
Ti (OR ² ) _m Cl _{4 -m}
(Wherein R ² is an alkyl group having 1 to 10 carbon atoms, m is an integer of 0 to 4, or a prime number)

(3) adding an alkoxysilane compound represented by the following formula (3) to the solid catalyst during the reaction of step (2) or after completion of the reaction of step (2);
(3)
R ³ _n Si (OR ⁴ ) _{4 -n}
(Wherein R ³ and R ⁴ are each an alkyl group having 1 to 10 carbon atoms, n is an integer of 0, 1 or 2, and when n is 2, two R ^{4 s} are the same or different.)
The method according to claim 1,
Wherein the solid catalyst is polymerized in the presence of a cocatalyst represented by the following general formula (4).

≪ Formula 4 >
AlR ⁵ ₃
(Wherein R < ⁵ > is an alkyl group having 1 to 16 carbon atoms)
9. The method of claim 8,
The promoter is at least one selected from triethylaluminum, trimethylaluminum, trinormalpropylaluminum, trinormalbutylaluminum, triisobutylaluminum, trinormalhexylaluminum, trinormaloctalaluminum and tri-2-methylpentylaluminum Of the polyethylene resin composition for a bottle cap.
A molded article produced by the process for producing a polyethylene resin composition according to any one of claims 1 to 9.